“Mr. Gingrich is the Don Draper of 2012: When it comes to his character record, he’s a very fine, empty suit with a broken zipper,” the Rev. Albert Calaway of Indianola wrote, referring to the lecherous character on the show “Mad Men.” “Christians in Iowa – and I understand many of his old U.S. House colleagues as well – desperately want to see a changed man, yet we keep on seeing a glib, wordy cheater. On all fronts, Newt should just be faithful.”

The Family Leader’s 14-point marriage pledge calls for opposition to anything but one-man/one-woman marriage. Three other Republican presidential candidates, Michele Bachmann, Rick Santorum and Rick Perry, have signed the pledge. But Gingrich, who has been married three times, has not.

Calaway, a retired Assemblies of God minister who founded the group Truth Values & Leadership, said he is not backing any candidate yet. He mocked reports that Gingrich endorsed the Family Leader’s marriage pledge Monday. “When you ‘endorse’ a check, you sign it. When you get married, you sign the license,” he wrote. “When you sign a contract or covenant, that means you are all-in. But, Mr. Gingrich has yet to sign for many things which Christian Iowa cares about very deeply.”

The Rev. Cary Gordon, pastor of Sioux City’s Cornerstone Church, added to Calaway’s criticism of Gingrich. “When you stand before the altar and say your marriage vows, you either mean it, or you don’t,” wrote Gordon, who is backing Santorum. “Sad to say, but by endorsing some of the Vow without signing it, I think Mr. Gingrich is dodging a sacred commitment which Iowa’s Christians really expect from him.”

Gingrich’s spokesman did not immediately respond to a request for comment.